Table 3 Results of a univariate Generalized Estimating Equation Model Predicting smear positivity according to sex

Age

 40-59 years (versus < 40 years)

2.76 (1.24-6.14)

0.013

1.11 (0.32-3.89)

0.867

 ≥ 60 years (versus < 40 years)

1.03 (0.37-2.82)

0.961

2.45 (0.73-8.21)

0.146

BMI

 ≥23 (versus <23)

1.70 (0.71-4.10)

0.235

1.16 (0.39-3.42)

0.787

Respiratory symptoms

 any symptom

3.73 (1.57-8.87)

0.003

3.85 (1.44-10.28)

0.007

 cough

3.02 (1.42-6.42)

0.004

5.31 (2.03-13.92)

0.001

 sputum

3.72 (1.78-7.77)

<0.001

1.61 (0.56-4.63)

0.376

 hemoptysis

2.26 (0.38-13.33)

0.369

7.96 (1.91-33.21)

0.004

 duration (<3 weeks versus ≥3 weeks)

3.71 (1.77-7.78)

0.001

4.93 (1.83-13.30)

0.002

General symptoms

2.52 (1.19-5.37)

0.016

1.74 (0.44-6.94)

0.431

Smoking

 current smoking

1.38 (0.68-2.81)

0.374

0.53 (0.14-2.09)

0.374

 previous smoking

1.37 (0.63-2.98)

0.430

0.58 (0.14-2.40)

0.451

 1-10 pack-years (versus 0 pack-years )

1.85 (0.65-5.25)

0.250

0.58 (0.14-2,49)

0.464

 ≥ 10 pack-years (versus 0 pack-years )

2.93 (1.22-7.07)

0.016

0.65 (0.18-2.36)

0.507

Radiographic extent

 moderate or far-advanced (versus minimal)

4.42 (2.07-9.45)

<0.001

1.23 (0.37-4.10)

0.732

 cavity

5.27 (2.24-11.47)

<0.001

2.02 (0.342-11.91)

0.438

Gross appearance of sputum specimens

 sputum (versus saliva )

1.70 (1.08-2.67)

0.021

1.51 (0.70-3.29)

0.297

 purulent, bloody (versus saliva, mucoid)

2.04 (1.33-3.12)

0.001

2.96 (1.46-6.01)

0.003

Volume of sputum specimens

 ≥1 ml (<1 ml versus ≥1 ml)

1.18 (0.74-1.88)

0.482

2.81 (1.43-5.51)

0.003

 ≥2 ml (<2 ml versus ≥2 ml)

1.10 (0.87-1.39)

0.433

2.27 (0.99-5.17)

0.052

 ≥3 ml (<3 ml versus ≥3 ml)

1.12 (0.87-1.44)

0.396

1.74 (0.57-5.31)

0.331

 ≥4 ml (<4 ml versus ≥4 ml)

1.09 (0.90-1.32)

0.372

3.89 (1.89-7.98)

<0.001

 ≥5 ml (<5 ml versus ≥5 ml)

1.01 (0.87-1.16)

0.933

3.31 (0.84-13.06)

0.088